Exhaust Control Valve Controlling Exhaust Gas Flow in a Turbocharger System

ABSTRACT

Methods and systems for adjusting a branch communication valve in a dual scroll turbocharger system are provided. In one example, a method may include adjusting a position of a valve arranged between a first adaptor and a second adaptor to enable mixing of exhaust received from an exhaust manifold, the exhaust delivered to a first scroll and a second scroll of a turbocharger to drive a turbine during certain engine operating conditions.

FIELD

The present disclosure relates to a turbocharger of an engine.

BACKGROUND/SUMMARY

Twin, or dual, scroll turbocharger configurations may be used inturbocharged engines. A twin scroll turbocharger configuration mayseparate an inlet to a turbine into two separate passages connected toexhaust manifold runners. In this way, exhaust from the enginecylinders, whose exhaust gas pulses may interfere with each other, arefluidically separated.

For example, on an I4 engine with a cylinder firing order of exhaustmanifold runners 1-3-4-2, exhaust manifold runners 1 and 4 may beconnected to a first inlet of a twin scroll turbine and exhaust manifoldrunners 2 and 3 may be connected to a second inlet of said twin scrollturbine, where the second inlet is different and fluidically separatedfrom the first inlet. In this way, separating exhaust gas pulses mayresult in an increase in efficiency of exhaust gas delivery to a turbinein some cases.

However, under some engine operating conditions, separating exhaust gaspulses as described above may reduce an efficiency of exhaust gasdelivery to a turbine. For example, under certain engine operatingconditions, e.g., high speed and high load conditions, separatingexhaust gas pulses may result in an increase in backpressure and pumpingwork. This increase in backpressure and pumping work may be due to morerestrictive, lower volume passages between the exhaust and the turbinein a dual scroll turbine, as compared to a passage that is not separatedin a single scroll turbine. As such, the amount of exhaust gas in thecylinder may raise the pressure in the lower volume passages compared tothe relatively larger volume, unseparated passage. The increasedbackpressure may also result in higher levels of residual gas havingexcessive temperatures in the cylinder, thereby reducing the engine'soutput power and engine efficiency.

One example approach for reducing backpressure and pumping work in atwin scroll turbocharger has been shown by Styles et al. in U.S.2014/0219849. Herein, systems positioning a branch communication valvebetween a first scroll and a second scroll in a twin (e.g., dual) scrollturbocharger system are provided. In an example, a branch communicationvalve may be positioned in a passage within a wall separating a firstscroll and a second scroll of the twin turbocharger. In an openposition, the branch communication valve may increase fluidcommunication between the first and second scroll, and in a closedposition, the branch communication valve may decrease fluidcommunication between the first and second scroll. The branchcommunication valve of Styles et al. comprises a valve plate rotatableabout a hinge, the hinge positioned within a recess of the secondscroll. The valve plate is movable between a first position, wherein thevalve plate covers the opening in the dividing wall, and a secondposition, wherein the valve plate is within the recess.

The inventors herein have recognized a potential issue with the exampleapproach of Styles et al. For example, there may be cost, weight, andpackaging penalties associated with the above configuration of branchcommunication valve having a valve plate rotatable about a hinge in theturbocharger and engine system. For example, the hinge is shown in arecess of the second scroll, which increases the size and complexity ofmanufacturer of the turbocharger system. Further, the branchcommunication valve comprises a valve plate and valve stem, the valveplate slidable to cover the opening. As such, these components, such asthe valve plate and valve stem, are exposed to high temperatures and,thus, may wear overtime. The components may also be an additional burdenon an engine control and monitoring system when the aforementionedsystem is adjusted on engine operating conditions.

The inventors herein have identified an approach to at least partlyaddress the above issue. In an example, a method for an engine isprovided, comprising adjusting a position of a valve arranged between afirst adaptor and a second adaptor to enable mixing of exhaust receivedfrom an exhaust manifold responsive to engine load and engine speed, theexhaust delivered to a first scroll and a second scroll of aturbocharger, wherein the first adaptor includes a first divider, thesecond adaptor includes a second divider, and the valve includes a thirddivider. In this way, there may be a reduction in flow restrictionduring certain engine operating conditions, such as high engine speedand/or high engine load.

In one example, the method may adjust a valve to provide one of aseparation of exhaust and mixing of exhaust, wherein the valve varies adegree of mixing of exhaust received from an exhaust manifold. As such,each of the first adaptor and second adaptor may be stationary, whilethe valve may rotate about the central axis to selectively vary a degreeof alignment of the third divider of the valve relative to the firstdivider of the first adaptor and the second divider of the secondadaptor. In this way, the method may provide a straightforward anduncomplicated controls and systems for regulating pulsation flow to theturbocharger based on various engine operating conditions.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of an example engine including a dual(twin) scroll turbocharger and a branch communication valve.

FIGS. 2A-2D illustrate schematic views of an example branchcommunication valve in a first and a second position.

FIGS. 3A-3B show schematic views of an example branch communicationvalve in a first and a second position, and a flow of exhaust gas froman exhaust manifold, through a valve assembly, and into a first andsecond scroll.

FIG. 4 shows an example method for adjusting an example branchcommunication valve.

FIG. 5 shows an example method for adjusting an example branchcommunication valve and wastegate.

FIG. 6 shows an example method for adjusting an example branchcommunication valve for detection of cylinder imbalance.

FIG. 7 shows an example operation plot for adjusting an example branchcommunication valve responsive to engine operating conditions.

DETAILED DESCRIPTION

The following description relates to systems and methods for controllingfluid communication between a first and second scroll in a dual (i.e.twin) scroll turbocharger system having a branch communication andwastegate valve in an engine system, such as the engine systems inFIG. 1. As shown in FIGS. 2A and 2B, in some embodiments, a branchcommunication valve may be provided, wherein the branch communicationvalve may be coupled to a first adaptor at a second end of the branchcommunication valve, and coupled to a second adaptor at a first end ofthe branch communication valve. The aforementioned system having thebranch communication valve, the first adaptor, and the second adaptor,may control an increase and/or decrease in fluid communication betweenthe first and second scrolls, and exhaust gas flow through the turbine.A position and/or orientation of the branch communication valve may beadjusted relative to a position and/or orientation of the first andsecond adaptors during various engine operating conditions. For example,adjusting the branch communication valves to a second position may allowincreased fluid communication between the first and second scrolls,while adjusting the branch communication valves to a first position mayreduce fluid communication between the first and second scrolls, asshown in FIGS. 3A and 3B. Thus, an amount of fluidic communication andconveyance between the first scroll and the second scroll may beadjusted based on engine operating conditions, as shown below inreference to FIG. 4. Example valve adjustments based on engine operatingconditions are shown in FIG. 5.

Turning now to FIG. 1, a schematic diagram of an engine 10, which may beincluded in a propulsion system of a vehicle, is shown. Engine 10 may becontrolled at least partially by a control system including controller12 and by input from a vehicle operator 14 via an input device 16.Controller 12 may be a microcomputer, including a microprocessor unit,input/output ports, an electronic storage medium for executable programsand calibration values, random access memory, keep alive memory, and adata bus. As depicted, controller 12 may receive input from a pluralityof sensors (not shown), which may include user inputs and/or sensors(such as transmission gear position, gas pedal input, exhaust manifoldtemperature, air-fuel ratio, vehicle speed, engine speed, mass airflowthrough the engine, boost pressure, ambient temperature, ambienthumidity, intake air temperature, cooling system sensors, and others).The controller may also send a plurality of control signals to variousengine actuators (not shown) in order to adjust engine operation basedon signals received from the sensors (not shown). In this example, inputdevice 16 includes an accelerator pedal and a pedal position sensor 18for generating a proportional pedal position signal PP. Engine 10 may beincluded in a vehicle such as a road vehicle, among other types ofvehicles. While the example applications of engine 10 will be describedwith reference to a vehicle, it should be appreciated that various typesof engines and vehicle propulsion systems may be used, includingpassenger cars, trucks, etc. Engine 10 may include a plurality ofcombustion chambers (i.e., cylinders). In the examples shown in FIG. 1,engine 10 may include combustion chambers 20, 22, 24, and 26, arrangedin an inline four configuration. It should be understood, however, thatthough FIG. 1 shows four cylinders, engine 10 may include any number ofcylinders. For example, engine 10 may include any suitable number ofcylinders, e.g., 2, 3, 4, 5, 6, 8, 10, 12, or more cylinders in anyconfiguration, e.g., V-6, I-6, V-12, opposed 4, etc. Though not shown inFIG. 1, each combustion chamber (i.e. cylinder) of engine 10 may includecombustion chamber walls with a piston positioned therein. The pistonsmay be coupled to a crankshaft so that reciprocating motions of thepistons are translated into rotational motion of the crankshaft. Thecrankshaft may be coupled to at least one drive wheel of a vehicle viaan intermediate transmission system, for example. Further, a startermotor may be coupled to the crankshaft via a flywheel to enable astarting operation of engine 10.

Each combustion chamber may receive intake air from an intake manifold28 via an air intake passage 30. Intake manifold 28 may be coupled tothe combustion chambers via intake ports. For example, in FIG. 1, intakemanifold 28 is shown coupled to cylinders 20, 22, 24, and 26 via intakeports 32, 34, 36, and 38, respectively. Each respective intake port maysupply air and/or fuel to the respective cylinder for combustion.

Each combustion chamber may exhaust combustion gases via an exhaust portcoupled thereto. For example, exhaust ports 40, 42, 44 and 46, are shownin FIG. 1 coupled to cylinders 20, 22, 24, 26, respectively. Eachrespective exhaust port may direct exhaust combustion gases from arespective cylinder to an exhaust manifold or exhaust passage.

Each cylinder intake port may selectively communicate with the cylindervia an intake valve. For example, cylinders 20, 22, 24, and 26 are shownin FIG. 1 with intake valves 48, 50, 52, and 54, respectively. Likewise,each cylinder exhaust port can selectively communicate with the cylindervia an exhaust valve. For example, cylinders 20, 22, 24, and 26 areshown in FIG. 1 with exhaust valves 56, 58, 60, and 62, respectively. Insome examples, each combustion chamber may include two or more intakevalves and/or two or more exhaust valves.

Though not shown in FIG. 1, in some examples, each intake valve andexhaust valve may be operated by an intake cam and an exhaust cam,respectively. Alternatively, one or more of the intake and exhaustvalves may be operated by an electromechanically controlled valve coiland armature assembly (not shown). The position of an intake cam may bedetermined by an intake cam sensor (not shown). The position of exhaustcam may be determined by an exhaust cam sensor (not shown).

Intake passage 30 may include a throttle 64 having a throttle plate 66.In one example, a position of throttle plate 66 may be varied bycontroller 12 via a signal provided to an electric motor or actuatorincluded with throttle 64, a configuration that is commonly referred toas electronic throttle control (ETC). In this manner, throttle 64 may beoperated to vary the intake air provided to the combustion chambers. Theposition of throttle plate 66 may be provided to controller 12 bythrottle position signal TP from a throttle position sensor 68. Intakepassage 30 may include a mass air flow sensor 70 and a manifold airpressure sensor 72 for providing respective signals MAF and MAP tocontroller 12. In some embodiments, MAP and MAF may not both be present,and only one sensor may be used.

In FIG. 1, fuel injectors are shown coupled directly to the combustionchambers for injecting fuel directly therein in proportion to a pulsewidth of a signal FPW received from controller 12 via an electronicdriver, for example. For example, fuel injectors 74, 76, 78, and 80 areshown in FIG. 1 coupled to cylinders 20, 22, 24, and 26, respectively.In this manner, the fuel injectors provide what is known as directinjection of fuel into the combustion chamber.

Each respective fuel injector may be mounted in the side of therespective combustion chamber or on the top of the respective combustionchamber, for example. In other examples, one or more fuel injectors maybe arranged in the air intake manifold 28 in a configuration thatprovides what is known as port injection of fuel into the intake ports(e.g., intake ports 32, 34, 36, and 38) upstream of combustion chambers.Though not shown in FIG. 1, fuel injectors may be configured to deliverfuel received via a high pressure fuel pump (not shown) and a fuel rail(not shown). Alternatively, fuel may be delivered by a single stage fuelpump at lower pressure, in which case the timing of the direct fuelinjection may be more limited during the compression stroke than if ahigh pressure fuel system is used. Further, the fuel tank may have apressure transducer providing a signal to controller 12. In someexamples, fuel may be injected directly into each respective combustionchamber (referred to as direct injection). Indirect injection may beused in other examples.

The combustion chambers of engine 10 may be operated in a compressionignition mode, with or without an ignition spark. In some examples, adistributorless ignition system (not shown) may provide an ignitionsparks to spark plugs coupled to the combustion chambers in response tocontroller 12. For example, spark plugs 82, 84, 86, and 88 are shown inFIG. 1 coupled to cylinders 20, 22, 24, and 26, respectively.

As mentioned above, intake passage 30 may communicate with one or morecylinders of engine 10. In some embodiments, one or more of the intakepassages may include a boosting device such as a turbocharger 90.Turbocharger 90 may be include a turbine 92 and a compressor 94 coupledon a common shaft 96. The blades of turbine 92 may be caused to rotateabout the common shaft 96 as a portion of the exhaust gas stream or flowdischarged from engine 10 impinges upon the blades of the turbine.Compressor 94 may be coupled to turbine 92 such that compressor 94 maybe actuated when the blades of turbine 92 are caused to rotate.

When actuated, compressor 94 may then direct pressurized fresh gas toair intake passage 28 where it may then be directed to engine 10. Thespeed of the turbine may be inferred from one or more engine operatingconditions. In some examples, the rotational speed of the turbine 92 maybe measured with a sensor. For example a speed sensor 97 may be coupledwith common shaft 96. A signal indicative of the speed may be delivered,for example, to the controller 12.

Engine 10 may employ a dual scroll (or twin scroll or two-pulse)turbocharger system 98 wherein at least two separate exhaust gas entrypaths flow into and through turbine 92. A dual scroll turbochargersystem may be configured to separate exhaust gas from cylinders whoseexhaust gas pulses interfere with each other when supplied to turbine92. For example, FIG. 1 shows a first scroll 100 and a second scroll102, wherein each of the first scroll and second scroll may be used tosupply separate exhaust flow to turbine 92. The cross-sectional shape offirst scroll 100 and second scroll 102 may be of various shapes,including circular, square, rectangular, D-shaped, etc.

Turbine 92 may include at least one wastegate to control an amount ofboost provided by said turbine. In a dual scroll system, both scrollsmay share a wastegate to control an amount of exhaust gas which passesthrough turbine 92. For example, in FIG. 1, the first scroll 100 andsecond scroll 102 include a wastegate 104. Exhaust flow throughwastegate 104 may be controlled by a valve, such as a valve 140discussed below, to regulate the amount of exhaust gas bypassing turbine92. In one embodiment, an area of an opening of the wastegate 104 may bepositioned equally open to each of the scrolls, such that substantiallysimilar amounts of exhaust gas flow may exit each of the scrolls intowastegate 104 during some conditions.

For example, if a four-cylinder engine (e.g., an 14 engine such as shownin FIG. 1) has a firing sequence of 1-3-4-2 (e.g., cylinder 20 followedby cylinder 24 followed by cylinder 26 followed by cylinder 22), thencylinder 20 may be ending its expansion stroke and opening its exhaustvalves while cylinder 22 still has its exhaust valves open. In asingle-scroll or undivided exhaust manifold 41, the exhaust gas pressurepulse from cylinder 20 may interfere with the ability of cylinder 22 toexpel its exhaust gases. However, by using a dual scroll turbochargersystem, wherein exhaust ports 40 and 46 from cylinders 20 and 26 areconnected to one inlet of the first scroll 100, and exhaust ports 42 and44 from cylinders 22 and 24 are connected to the second scroll 102,exhaust pulses or gas flow may be separated, and pulse energy drivingthe turbine may be increased.

Exhaust gases exiting turbine 92 and/or a wastegate via a firstwastegate 104 and/or a second wastegate 108 may pass through an emissioncontrol device 112. Emission control device 112 can include multiplecatalyst bricks, in one example. In another example, multiple emissioncontrol devices, each with multiple bricks, can be used. In someexamples, emission control device 112 may be a three-way type catalyst.In other examples, emission control device 112 may include one or aplurality of a diesel oxidation catalyst (DOC), selective catalyticreduction catalyst (SCR), and a diesel particulate filter (DPF). Afterpassing through emission control device 112, exhaust gas may be directedto a tailpipe 114.

Engine 10 may include an exhaust gas recirculation (EGR) system 116. EGRsystem 116 may deliver a portion of exhaust gas exiting engine 10 intothe engine air intake passage 30. The EGR system includes an EGR conduit118 coupled to a conduit or exhaust passage 122, downstream of theturbine 92, and to the intake passage 30. In some examples, EGR conduit118 may include an EGR valve 120 configured to control an amount ofrecirculated exhaust gas. As shown in FIG. 1, EGR system 116 is a lowpressure EGR system, routing exhaust gas from downstream of the turbine92 to upstream of the compressor 94. In some examples, an EGR cooler(not shown) may be placed along EGR conduit 118 which may serve toreduce the temperature of the exhaust gas being re-circulated. Inanother example, a high pressure EGR system may be used in addition toor in place of the low pressure EGR system. As such, the high pressureEGR system may route exhaust gas from one or more of the first scroll100 and second scroll 102, upstream of the turbine 92, to the intakepassage 30, downstream of the compressor 34.

Under some conditions, EGR system 116 may be used to regulate thetemperature and or dilution of the air and fuel mixture within thecombustion chambers, thus providing a method of controlling the timingof ignition during some combustion modes. Further, during someconditions, a portion of combustion gases may be retained or trapped inthe combustion chamber by controlling exhaust valve timing.

In some examples, controller 12 may be a microcomputer, including amicroprocessor unit, input/output ports, an electronic storage mediumfor executable programs and calibration values, random access memory,keep alive memory, and a data bus. As depicted, controller 12 mayreceive input from a plurality of sensors, which may include user inputsand/or sensors (such as transmission gear position, gas pedal input,exhaust manifold temperature, air-fuel ratio, vehicle speed, enginespeed, mass airflow through the engine, ambient temperature, ambienthumidity, intake air temperature, cooling system sensors, and others).The controller may also send a plurality of control signals to variousengine actuators (not shown) in order to adjust engine operation basedon signals received from the sensors (not shown). In this example, inputdevice 16 includes an accelerator pedal and a pedal position sensor 18for generating a proportional pedal position signal PP. Further,controller 12 is shown in FIG. 1 receiving various signals from sensorscoupled to engine 10, in addition to those signals previously discussed,including: engine coolant temperature (ECT) from a temperature sensor128; an engine position sensor 130, e.g., a Hall effect sensor sensingcrankshaft position. Barometric pressure may also be sensed (sensor notshown) for processing by controller 12. In some examples, engineposition sensor 130 produces a predetermined number of equally spacedpulses every revolution of the crankshaft from which engine speed (RPM)can be determined. Additionally, various sensors may be employed todetermine turbocharger boost pressure. For example, a pressure sensor132 may be disposed in intake passage 30 downstream of compressor 94 todetermine boost pressure. Additionally, each scroll of the dual scrollturbocharger system 98 may include various sensors for monitoringoperating conditions of the dual scroll system. For example, the firstscroll 100 may include an exhaust gas sensor 134 and the second scroll102 may include an exhaust gas sensor 136. Exhaust gas sensors 134 and136 may be any suitable sensor for providing an indication of exhaustgas air/fuel ratio such as a linear oxygen sensor or UEGO (universal orwide-range exhaust gas oxygen), a two-state oxygen sensor or EGO, a HEGO(heated EGO), a NOx, HC, or CO sensor. In some cases a single sensor maybe used to, for example, sense an air/fuel ratio. The single sensor maybe used in place of using sensors 134 and 136, and may be positioned,for example, downstream from the turbine in the conduit or exhaustpassage 122. In other examples, one or more additional or alternativesensors, such as sensor 137, may be included to sense the air/fuel ratioimmediately downstream of a valve assembly (e.g., valve assembly 145described below), the valve assembly configured to mix exhaust flowdownstream of the combustion chambers.

Each scroll may receive exhaust gas from a specific set of cylinder viaspecific exhaust manifold segments and distinct inlets. Exhaust gasesflowing through the first scroll 100 and exhaust gases flowing throughthe second scroll 102 are separated by a dividing wall 138. As discussedabove, separating exhaust gas flow (i.e. exhaust gas pulses) in thefirst and second scrolls may increase low-end engine torque and reduce aduration to achieve said torque. As a result, during certain conditionssuch as high engine load, separating the exhaust gas pulses may resultin an increase in efficiency of exhaust gas flow delivery to turbine 92.However, during some engine operating conditions, separating exhaust gaspulses may reduce efficiency of exhaust gas delivery to the turbine. Forexample, during high engine speed, separating exhaust gas pulses asdescribed above may increase backpressure and pumping work due, in part,to a more restrictive and lower scroll volume between the exhaust valveand the turbine compared to a combined, unseparated single turbine inletscroll. In other words, a volume of exhaust gas exiting the cylinder(s)may raise the pressure more in the aforementioned dual scrollconfiguration, since the separated first scroll and second scroll mayhave a relatively smaller volume as compared to a scroll configurationwhere the scrolls or passages are not separated. In response, enginepower output may be reduced.

Increasing fluid communication and conveyance between and/or upstream ofthe first and second scrolls during certain engine operating conditions,such as high speed and/or high load, may allow increased engineefficiency and power output. Thus, engine 10 may further include a valveassembly 145, wherein the valve assembly 145 may include a first adaptor150, a second adaptor 152, and/or a branch communication valve 154(herein referred to as valve 154) coupled between each of the firstadaptor 150 and second adaptor 152. The valve assembly 145 may beconfigured to selectively allow mixing of exhaust from a first set, orbranch, of cylinders, or combustion chambers (e.g., cylinders 20 and26), and a second set, or branch, of cylinders, or combustion chambers(e.g., cylinders 22 and 24) upstream of each of the inlets of the firstscroll 100 and second scroll 102. As such, in one embodiment, valveassembly 145 may be arranged downstream of the exhaust manifold 41having the first set of cylinders (e.g., cylinders 20 and 26), and asecond set of cylinders (e.g., cylinders 22 and 24), and upstream ofeach of the inlets of the first scroll 100 and second scroll 102. Inanother embodiment, valve assembly 145 may be integrated in the firstscroll 100 and the second scroll 102. Of note, the term “valve” as usedherein may be understood to mean an obstruction, which may be movable orpositionable to control a flow of fluid, and may be understood to mean amovable obstruction, which may be housed in and/or coupled with variouscomponents such as a housing or body, etc.

In one embodiment, first adaptor 150 may be operably coupled and in facesharing contact with an outlet of exhaust manifold 41 of engine 10downstream of the cylinders, as shown in FIG. 1. Said another way, firstadaptor 150 may be configured to receive exhaust gas from the first setof cylinders, such as cylinders 20 and 26, and the second set ofcylinders, such as cylinders 22 and 24 of exhaust manifold 41.

Similarly, second adaptor 152 may be operably coupled to and inface-sharing contact with an inlet of first scroll 100 and/or an inletof second scroll 102 of the dual scroll turbocharger system 98. As willbe discussed in detail in FIG. 2, a first opening and a second openingof the second adaptor 152 may align with the first scroll 100 and secondscroll 102, respectively, of dual scroll turbocharger system 98. Inanother example, the first opening and second opening of the firstadaptor 150 may also align with the first scroll 100 and second scroll102, respectively, of the dual scroll turbocharger system 98.

In one embodiment, valve 154 may be provided between the first adaptor150 and second adaptor 152 to selectively allow or enable mixing of theexhaust from the first set of cylinders (e.g., cylinders 20 and 26), andthe second set of cylinders (e.g., cylinders 22 and 24), the exhaust tobe delivered downstream to each of the inlets of the first scroll 100and second scroll 102 during certain engine operating conditions. In oneembodiment, valve 154 may be configured to rotate independently relativethe first adaptor 150 and the second adaptor 152, such that valve 154may be opened completely, opened partially, and/or closed to each of thefirst scroll 100 and/or second scroll 102. The position of valve 154 maybe varied by controller 12 via signals provided to an actuator 153included with valve 154. In one example, actuator 153 may be electricactuators (e.g., electric motors). For example, valve 154 may bepositionable or adjustable via one or more signals received fromcontroller 12 in a continuous manner through selected positions orranges, discussed below. In one example, valve 154 may be adjusted viarotations in a continuous manner in one direction (e.g., clockwise). Inanother example, valve 154 may be adjusted via rotations in more thanone direction (e.g., clockwise and counterclockwise). In yet anotherexample, valve 154 may be adjusted via rotations in an intermittentmanner, such that the valve 154 may only be moved to pre-determined, ordiscrete, positions.

Thus, the valve 154 may be adjusted between selected positions. Forexample, valve 154 may be movable between a first position (e.g., aclosed position) and a second position (e.g., an opened position), asshown in reference to FIGS. 2 and 3. As an example, adjusting valve 154to the first position may reduce fluidic communication and conveyance ofexhaust gas between a plurality of cylinders, the exhaust gas to bedelivered to the turbine, e.g., turbine 92. In contrast, the secondposition may provide fluid communication and conveyance of exhaust gasbetween a plurality of cylinders, thereby allowing mixed exhaust (e.g.,exhaust from one or more branches of the exhaust manifold) to flow toeach of the first scroll 100 and second scroll 102.

Specifically, in one embodiment, during other vehicle operatingconditions such as low load and low engine speed, valve 154 may beclosed completely (e.g., in the first position), such that exhaust fromeach of the first set of cylinders (e.g., cylinders 20 and 26), and thesecond set of cylinders (e.g., cylinders 22 and 24) may flow in separateand single flow paths to each of the inlets of the first scroll 100 andsecond scroll 102. In other words, valve 154 may be completely closedsuch that considerably no exhaust gas from the first set of cylinders(e.g., cylinders 20 and 26), and the second set of cylinders (e.g.,cylinders 22 and 24) may communicate and mix via valve assembly 145. Assuch, substantially all exhaust gas flow from the first set of cylindersand the second set of cylinders may be individually and independentlydirected to the turbine, such as turbine 92, via the valve assembly 145and the first scroll 100 and second scroll 102.

In another embodiment, during certain vehicle operating conditions suchas high load and high engine speed, valve 154 may be opened completely(e.g., in the first position), such that an amount of exhaust gas fromthe first set of cylinders (e.g., cylinders 20 and 26) may mix andcombine with an amount of exhaust gas from the second set of cylinders(e.g., cylinders 22 and 24). Likewise, an amount of exhaust gas from thesecond set of cylinders (e.g., cylinders 22 and 23) may mix and combinewith an amount of exhaust gas from the first set of cylinders (e.g.,cylinders 20 and 26). In other words, a portion of exhaust gas from thefirst set of cylinders and the second set of cylinders may be mix andcombine, and subsequently directed to the turbine, such as turbine 92,via the first scroll 100 and second scroll 102. As a result, turbulencegenerated from said mixing between exhaust flow paths from a pluralityof cylinders of engine 10 may reduce flow restriction within the valveassembly, thereby reducing pumping loss and increasing engine and fuelefficiency during desired engine operating conditions. Further, enginepumping loss may be reduced by reducing pressure loss across theturbine. When the valve is open, all exhaust gas from one or morecylinders may flow through both scrolls, therefore reducing pressureloss due to an increase of cross-section area of flow passage across theturbine.

In yet another embodiment, valve 154 may be opened a metered amount suchthat exhaust communication in valve assembly 154 may be restricted to adesired amount. In other words, only a portion of the amount of exhaustgas from the first set of cylinders (e.g., cylinders 20 and 26), and thesecond set of cylinders (e.g., cylinders 22 and 24) upstream of each ofthe inlets of the first scroll 100 and second scroll 102 during certainengine operating conditions. As such, said portion of the amount ofexhaust gas from the first and second set of cylinders that may combineand mix is less than the amount of exhaust gas from the first and secondset of cylinders that may mix and combine when valve 154 is completelyor fully opened.

As a result, adjustments to a position of valve 154 may control arotational speed of the turbine 92, as described, and in turn, regulatethe speed of compressor 94. Thus, in some embodiments, a valve, such asvalve 154, may enable mixing of exhaust received from an exhaustmanifold responsive to engine load and engine speed, the exhaustdelivered to a first scroll and a second scroll of the dual scrollturbocharger system 98 in engine 10. Increasing fluid communication andconveyance may include allowing exhaust gas from separate branches ofthe exhaust manifold to mix via valve assembly 145 when valve 154 is inthe second and/or third position.

In alternative embodiments, a valve, such as valve 154 may be positionedto provide control of exhaust gas through the first wastegate 104 and/orthe second wastegate 108. As such, wastegate control may includeallowing at least a portion of exhaust gas from each of first scroll 100and second scroll 102 to enter first wastegate 104 and/or secondwastegate 108, thereby bypassing turbine 92. In other examples,wastegate control may include closing the wastegate to preventsubstantially all exhaust gas from the first and second scrolls (and/oradditional scroll(s)) from bypassing the turbine. Since the position ofvalve 154 may control the rotational speed of the turbine, in someexamples, a wastegate position may also be responsive to the position ofvalve 154 (e.g., a metered or prescribed amount, or fully opened orfully closed), as well as to one or more engine operating conditions,such as engine speed, engine load, desired or demanded torque, and/orincreasing or decreasing torque.

In other words, a wastegate position may be adjusted based on theposition (e.g., amount of opening) of valve 154. For example, an amountof opening of first wastegate 104 and/or second wastegate 108 may bebased on the position of valve 154 and torque demanded, as will bediscussed in reference to FIG. 5. In one example, the amount of openingof one or more wastegates may be greater when valve 154 is in the secondposition as compared to the amount of opening of one or more wastegateswhen valve 154 is in the first position during a condition when torquedemand is increasing. In another example, the amount of opening of oneor more wastegates may be less when valve 154 is in the first positionas compared to the amount of opening of one or more wastegates whenvalve 154 is in the second position during a condition when torquedemand is decreasing.

In yet another example, detection of cylinder imbalance may be based on,in part, by the position of valve 154, or the amount of opening of valve154, as will be discussed in FIG. 6. For example, in response to arequest for detecting a cylinder imbalance, valve 154 may be adjusted tothe first position from the second position or third position.Consequently, an air-fuel ratio in each of the first and second scrollsmay be measured, and based on said measured air-fuel ratio, one of afuel injection amount and/or throttle valve may be adjusted. Otherarrangements not specifically illustrated may also be possible inaccordance with the present disclosure.

Now referring to FIGS. 2A and 2B, example exploded views of the valveassembly 145 comprising first adaptor 150, second adaptor 152, and abranch communication valve, such as valve 154, in a first position orstate (FIG. 2A) and a second position or state (FIG. 2B), are shown.Valve assembly 145 may have a central axis 202, such that each of thefirst adaptor 150, second adaptor 152, and valve 154 share the commoncentral axis 202. In one embodiment, central axis 202 is substantiallyparallel to a flow of exhaust gas in the first scroll 100 and secondscroll 102. As discussed above, a first end 222 of the first adaptor 150may engage with and couple to an outlet of the exhaust manifold, such asexhaust manifold 41 of engine 10. Similarly, a second end 228 of secondadaptor 152 may engage with and couple to an inlet of the first scroll100 and an inlet of the second scroll 102. Further, each of the firstadaptor 150 and second adaptor 152 may be immovable, or stationary, suchthat only valve 154 may be rotatable relative to each of the firstadaptor 150 and second adaptor 152. In other words, each of the firstadaptor 150 and second adaptor 152 may immovably fixed to the exhaustmanifold and each inlet of the first and second scrolls, respectively.

Valve 154 may be arranged between each of the first adaptor 150 andsecond adaptor 152 in an airtight but rotatable manner, such thatadjustments of valve 154 may be provided during certain engine operatingconditions. In particular, valve 154 may rotate in a directionperpendicular to the flow of exhaust gas about central axis 202 betweenone or more positions, e.g., first position, second position, and/or athird position of valve 154. A first end 230 of valve 154 may berotatably coupled to a second end 224 of the first adaptor 150, thesecond end 224 opposite the first end 222 of the first adaptor 150. Asecond end 232 of valve 154 may be rotatably coupled to a first end 226of the second adaptor 152, the first end 226 opposite the second end 228of the second adaptor 152. In this way, the first adaptor 150 may beconfigured to receive exhaust gas exiting the exhaust manifold 41 andallow exhaust flow through valve 154 and into turbine 92 via secondadaptor 152.

In the example shown in FIGS. 2A and 2B, each of the first adaptor 150and/or second adaptor 152 may be hollow and have cylindrical shapehaving an annular cross-section. In another example, each of the firstadaptor 150 and/or second adaptor 152 may have another geometric shape,such as a rectangular shape. Further, each of the first adaptor 150and/or second adaptor 152 may be hollow and include a divider arrangedalong an inner surface of each of the first adaptor 150 and/or secondadaptor 152. In other words, the divider of each of the first adaptor150 and/or second adaptor 152 may bisect an inner volume of each of thefirst adaptor 150 and/or second adaptor 152, respectively. For example,first adaptor 150 may include a first divider 210. Similarly, secondadaptor 152 may include a second divider 212. Each of the first divider210 and second divider 212 may be span a diameter along a longitudinallength of their respective adaptors. Said another way, first divider 210spans a diameter of first adaptor 150 and second divider 212 spans adiameter of the second adaptor 152, such that each of the first divider210 and second divider 212 crosses an inner volume of first adaptor 150and second adaptor 152, respectively. In addition, as shown in FIGS.2A-2B, each of the first divider 210 and second divider 212 may span anentirety of a longitudinal length of each of the first adaptor 150 andsecond adaptor 152, respectively.

In an alternative example, two or more dividers may be arranged on aninner surface of the first adaptor 150 and/or the second adaptor 152. Inanother example, the first adaptor 150 may have a single divider, whilethe second adaptor 152 may have two dividers. It will be appreciatedthat any number of dividers and combinations of dividers within eachadaptor may be provided, if desired. In yet another example, one or moredividers arranged within any adaptor may not span a diameter of theadaptor, but may instead span a length of a chord of the adaptor.

Each divider 210 of first adaptor 150 and divider 212 of second adaptor152 may form one or more openings within first adaptor 150 and secondadaptor 152, respectively. For example, divider 210 of first adaptor 150may form a first opening 204 and a second opening 214. Similarly,divider 212 of second adaptor 152 may form a first opening 206 and asecond opening 216.

In one embodiment, as shown in FIGS. 2A and 2B, an orientation of eachdivider 210 of first adaptor 150 and divider 212 of second adaptor 152may be substantially the same when valve assembly 145 is integrated inthe dual scroll turbocharger system 98. In other words, each divider 210and divider 212 may be angled and arranged in a substantially similarfashion with respect to central axis 202 within their respectiveadaptor, such that first opening 204 of first adaptor 150 aligns withfirst opening 206 of second adaptor 152, and second opening 214 ofadaptor 150 aligns with second opening 216 of adaptor 152.

In one embodiment, first opening 204 and second opening 214 of firstadaptor 150 may each substantially align with each outlet of exhaustmanifold 41 from one or more sets of cylinders of engine 10, as shown inFIG. 1. Said another way, first opening 204 of first adaptor 150 mayreceive exhaust gas from the first set of combustion chambers, orcylinders, such as cylinders 20 and 26, and second opening 214 of firstadaptor 150 may be arranged to receive exhaust gas from the second setof combustion chambers, or cylinders, such as cylinders 22 and 24.

Likewise, first opening 206 and second opening 216 of second adaptor 152may each be substantially aligned with an inlet of first scroll 100and/or an inlet of second scroll 102, respectively, of the dual scrollsystem 98. As such, first opening 206 and a second opening 216 at thesecond end 228 of the second adaptor 152 may deliver exhaust flow to thefirst scroll 100 and second scroll 102, respectively, of dual scrollturbocharger system 98. In one embodiment, the orientations of each ofthe divider 210 of first adaptor 150 and divider 212 of second adaptor152 may be substantially stationary or immovable, such that theorientation of each divider may not be adjusted relative to the otherdivider. In this way, only adjustment(s) to valve 154 may control anamount of mixing of exhaust flow through first adaptor 150 and secondadaptor 152 into the first scroll 100 and second scroll 102. However, inalternative embodiments not shown, the first adaptor 150 and/or thesecond adaptor 152 may be rotatable relative to one another.

As illustrated in FIGS. 2A and 2B, valve 154 may comprise a hollowcylinder. In another example, valve 154 may have another geometricshape. In one embodiment, valve 154 may rotate on central axis 202substantially perpendicular to a flow of exhaust gas within each of thefirst scroll 100 and the second scroll 102. In one embodiment, valve 154may include a third divider 220 that rotates on central axis 202substantially perpendicular to the exhaust flow within each of the firstand second scrolls. Similar to each of the first adaptor 150 and secondadaptor 152, the third divider 220 may span a diameter of valve 154. Inaddition, as shown in FIGS. 2A-2B, the third divider 220 may span anentirety of a longitudinal length of valve 154. In this way, adjustmentsto valve 154 may provide selective fluidic communication and conveyanceof exhaust gases from the first and second set of cylinders to the firstscroll 100 and the second scroll 102. In other embodiments, adjustmentsto valve 154 may provide selective fluidic communication and conveyancebetween one or more combinations of first scroll 100, second scroll 102,and/or the first wastegate 104 and/or second wastegate 108 to a pointdownstream from turbine 92.

In one embodiment, valve 154 may be adjusted and movable in a continuousmanner through selected ranges, positions, or states via actuator 153responsive to one or more signals received from controller 12. Forexample, valve 154 may be adjusted via rotations about central axis 202in a continuous manner in a first direction (e.g., counterclockwise). Inanother example, valve 154 may be adjusted via rotations about centralaxis 202 in the first direction and an opposite, second direction (e.g.,counterclockwise and clockwise). In yet another example, valve 154 maybe adjusted via rotations about central axis 202 in an intermittentmanner, such that the valve 154 may only be moved to pre-determined, ordiscrete, positions.

As shown in FIG. 2A, valve assembly 145 is depicted having first adaptor150, second adaptor 152, and valve 154, wherein the valve 154 is in afirst position. Likewise, FIG. 2B illustrates valve assembly 145 havingfirst adaptor 150, second adaptor 152, and valve 154, wherein the valve154 is in a second position. Valve 154 may rotate in a first direction,shown here as a direction 240, such that an orientation of the thirddivider 220 may vary between the first position and the second position,and/or any position therebetween. For example, valve 154 may rotateapproximately 90 degrees in direction 240 from the first position (FIG.2A) to the second position (FIG. 2B). As a result, the third divider 220of valve 154 may concomitantly rotate 90 degrees from the first positionto the second position. Each of the first position and second positionof valve 154 will be discussed in detail in reference to FIGS. 3A and3B. It shall be appreciated that when valve 154 is adjusted, firstadaptor 150 and/or adaptor 152 may be stationary, such that the firstadaptor 150 and/or second adaptor 152 are not rotationally adjusted, andremain immovably coupled to an outlet of the exhaust manifold 41 andeach inlet of the first and second scrolls, respectively.

Now turning to FIGS. 2C to 2D, example front views of valve assembly 145when valve 154 is in the first position (FIG. 2C) and in the secondposition (FIG. 2D) are shown. For purpose of orientation, the frontviews of the valve assembly 145 are shown such that the second adaptor152 is closest to a viewer, followed by the valve 154, and the firstadaptor 150 at the opposite end of the second adaptor. Moreover, thefront views of the valve assembly 145 are parallel to the central axis202, such that the flow of exhaust gas would be observed by the viewermoving towards the viewer. In this example, a front view of valveassembly 145 shown in FIG. 2C illustrates each orientation of the first,second, and third dividers discussed above when valve 154 is in thefirst position. As shown, the second divider 212 of the second adaptor152 overlaps with each of the third divider 220 of valve 154 and firstdivider 210 of first adaptor 150. In this way, only second divider 212of second adaptor 152 is viewable. In other words, an angle 242 betweeneach of the first divider 210 and second divider 212 relative to thirddivider 220 of valve 154 is approximately 0 degrees. Thus, valve 154, inthe first position, may be completely closed such that considerably noexhaust gas from the first set of cylinders (e.g., cylinders 20 and 26)and the second set of cylinders (e.g., cylinders 22 and 24) maycommunicate and mix in the dual scroll system 98. In other words,substantially all exhaust gas flow from the first set of cylinders andthe second set of cylinders may be separated and independently directedto the turbine, such as turbine 92, via the first scroll 100 and secondscroll 102.

Turning to FIG. 2D, the front view of valve assembly 145 shownillustrates each orientation of the first, second, and third dividersdiscussed above when valve 154 is in the second position, or openedposition. In one embodiment, the second divider 212 of the secondadaptor 152 overlaps with first divider 210 of first adaptor 150. Incontrast to FIG. 2C, the third divider 220 is arranged substantiallyperpendicular to each of the second divider 212 of the second adaptor152 and first divider 210 of first adaptor 150. In other words, angle242 between each of the first divider 210 and second divider 212relative to third divider 220 of valve 154 is approximately 90 degrees.As such, both second divider 212 of second adaptor 152 and third divider220 are viewable. Thus, in this example, valve 154 may be opened suchthat an amount of exhaust gas from the first set of cylinders (e.g.,cylinders 20 and 26) and the second set of cylinders (e.g., cylinders 22and 24) may communicate and mix in the dual scroll system 98.

In this way, exhaust flow through valve assembly 145 via adjustments tovalve 154 may be varied based on engine operating conditions, such asengine speed and load, wastegate position, and/or desired boost pressureand torque. For example, during high engine load and/or high enginespeed conditions, the position of valve 154 may be adjusted to allowexhaust gas flowing from the first set of cylinders (e.g., cylinders 20and 26), and the second set of cylinders (e.g., cylinders 22 and 24) tomix and combine. Therefore, engine pumping loss may be reduced byreducing pressure loss across the turbine. When the valve is open, allexhaust gas from one or more cylinders may flow through both scrolls,therefore reducing pressure loss due to an increase of cross-sectionarea of flow passage across the turbine. On the other hand, during lowengine load and/or low engine speed conditions, the valve 154 may beadjusted to reduce exhaust gas from the first set of cylinders (e.g.,cylinders 20 and 26) and the second set of cylinders (e.g., cylinders 22and 24) from mixing and combining since increased backpressure andpumping work on the pistons of engine 10 may not be a concern.

Now turning to FIG. 3A, an example exploded illustration of the valveassembly 145 is shown, wherein the valve 154 is in the first position. Afirst path of exhaust gas flow 312 from the first set of cylinders(e.g., cylinders 20 and 26), and a second path of exhaust gas flow 314from the second set of cylinders (e.g., cylinders 22 and 24) are shownexiting a first outlet 302 and a second outlet 304, respectively, ofexhaust manifold 41. In other words, exhaust gas from the first set ofcylinders may exit the first outlet 302 of exhaust manifold 41, andexhaust gas from the second set of cylinders may exit the second outlet304 of exhaust manifold 41. In one embodiment, when valve 154 is in thefirst position, the exhaust gas from the first set of cylinders mayfollow a flow path substantially the same or similar to the first pathof exhaust gas flow 312. Similarly when valve 154 is in the firstposition, the exhaust gas from the second set of cylinders may follow aflow path substantially the same or similar to the first path of exhaustgas flow 314.

The paths of exhaust flow (e.g., first path of exhaust gas flow 312and/or second path of exhaust gas flow 314) may be at least partiallycontrolled via adjustments valve 154. For example, the first path ofexhaust gas flow 312 and/or second path of exhaust gas flow 314 depictedin FIG. 3A may result when valve 154 is adjusted to be closed (e.g., inthe first position). Specifically, when valve 154 is in the firstposition, first opening 204 of first adaptor 150 aligns with firstopening 206 of second adaptor 152, and second opening 214 of firstadaptor 150 aligns with second opening 216 of second adaptor 152.Further, first opening 208 of valve 154 may also be aligned with each ofthe first opening 204 of adaptor 150 and first opening 206 of secondadaptor 152. Similarly, second opening 218 of valve 154 may also bealigned with each the second opening 214 of first adaptor 150 and thesecond opening 216 of second adaptor 152. As shown in FIG. 3A, whenvalve 154 is in the first position, each of the first opening 204 offirst adaptor 150, first opening 206 of second adaptor 152, and firstopening 208 of valve 154 may be substantially aligned with the firstscroll 100. When valve 154 is in the first position, each of the secondopening 214 of first adaptor 150, second opening 216 of second adaptor152, and second opening 218 of valve 154 may be substantially alignedwith the second scroll 102.

As such, the first position of valve 154 may substantially allow allexhaust flow from the first set of cylinders (e.g., cylinders 20 and 26)to be substantially contained and passed to the first scroll 100, andpass to turbine 92. Likewise, the first position of valve 154 maysubstantially allow all exhaust flow from the second set of cylinders(e.g., cylinders 22 and 24) to be substantially contained and passed tothe second scroll 102, and pass to turbine 92. In this way, adjustingvalve 154 to the first position may reduce fluid communication betweenexhaust from the branches or sets of cylinders. In alternativeembodiments, adjusting valve 154 to the first position may also restrictexhaust flow from the first and second scrolls to the wastegate. Thus,in the first position, valve 154 may direct exhaust flow from theexhaust manifold 41 to turbine 92 in a separate and independent manner.

In one embodiment, the valve 154 may be in the first position, or aposition substantially similar to the first position, during a conditionwhen one or more of engine load is less than a threshold load and/orengine speed is less than a threshold engine speed. As an example, thethreshold load may be an engine load above which it may be considered ahigh engine load condition, such as when the vehicle is towing a traileror hill climbing. In yet another example, the threshold engine speed maybe a speed at or above which excessive engine exhaust backpressure mayoccur in a dual scroll turbocharger system. In other examples, thethreshold load and/or threshold engine speed may be based on otherengine operating conditions. Now turning to FIG. 3B, an example secondposition of valve 154 is shown, wherein valve 154 may be substantiallyopened to each of the first scroll 100 and second scroll 102. In oneembodiment, when valve 154 is in the second position, the exhaust gasfrom the first set of cylinders may follow a flow path substantially thesame or similar to the first path of exhaust gas flow 312. Similarly,the exhaust gas from the second set of cylinders may follow a flow pathsubstantially the same or similar to the first path of exhaust gas flow314. For example, the first path of exhaust gas flow 312 and/or secondpath of exhaust gas flow 314 depicted in FIG. 3B may result when valve154 is adjusted to be opened (e.g., in the second position).

As shown, exhaust gas from the first set of cylinders (e.g., cylinders20 and 26) may exit first outlet 302 and enter first opening 204 offirst adaptor 150, while exhaust gas from the second set of cylinders(e.g., cylinders 22 and 24) may exit second outlet 304 and enter secondopening 214 of first adaptor 150 due to an orientation of the firstdivider 210 of first adaptor 150. Upon exiting first opening 204 offirst adaptor 150, the exhaust gas from the first set of cylinder may bediverted, or split, by third divider 220 of valve 154 into each of thefirst opening 208 and second opening 218 of valve 154 in approximatelyequal portions since the third divider 220 is shown positionedsubstantially perpendicular, or at a 90 degrees angle, relative to theorientation of the first divider 210. Similarly, upon exiting secondopening 214 of first adaptor 150, the exhaust gas from the second set ofcylinder may be diverted, or split, by third divider 220 of valve 154into each of the first opening 208 of valve 154 and second opening 218in approximately equal amounts. As such, valve 154 provides an interfaceor area in which combining and mixing of turbulent exhaust gas in dualscroll turbocharger system 98 may occur in a larger volume as comparedto the individual first and second scrolls.

Consequently, upon exiting first opening 208 of valve 154, the exhaustgas from the first set of cylinder may be again divided by seconddivider 212 into each of the first opening 206 of second adaptor 152,and second opening 216 of second adaptor 152 in approximately equalamounts since the second divider 212 is shown positioned substantiallyperpendicular, or at a 90 degrees angles, relative to the orientation ofthe third divider 220. Similarly, upon exiting second opening 218 ofvalve 154, the exhaust gas from the second set of cylinder may bedivided again by second divider 212 into each of the first opening 206and second opening 216 of second adaptor 152 in approximately equalamounts. As such, the second adaptor 152 may provide an additional aninterface or area in which combining and mixing of exhaust gas in dualscroll system 98 may occur in a larger volume as compared to theindividual first and second scrolls. In this way, backpressureexperienced by the pistons of engine 10 may be reduced, therebyincreasing engine efficiency and fuel economy.

The aforementioned paths of exhaust flow (e.g., first path of exhaustgas flow 312 and/or second path of exhaust gas flow 314) may be formedwhen valve 154 is adjusted to be opened (e.g., in the second position).Specifically, when valve 154 is in the second position, first opening204 of first adaptor 150 aligns with first opening 206 of second adaptor152, and second opening 214 of first adaptor 150 aligns with secondopening 216 of second adaptor 152. In contrast, first opening 208 ofvalve 154 may be rotated approximately 90 degrees relative to each ofthe first opening 204 of adaptor 150 and first opening 206 of secondadaptor 152. Similarly, second opening 218 of valve 154 may also berotated approximately 90 degrees relative to each of the second opening214 of first adaptor 150 and the second opening 216 of second adaptor152. As shown in FIG. 3B, when valve 154 is in the second position, eachof the first opening 204 of first adaptor 150 and first opening 206 ofsecond adaptor 152, and a portion (e.g., half) of the first opening 208of valve 154 may be substantially aligned with the first scroll 100.When valve 154 is in the second position, each of the second opening 214of first adaptor 150 and second opening 216 of second adaptor 152, and aportion (e.g., half) of the second opening 218 of valve 154 may besubstantially aligned with the second scroll 102.

In sum, when valve 154 is in the second position, or opened completely,an amount of exhaust gas from the first set of cylinders (e.g.,cylinders 20 and 26) may mix with an amount of exhaust gas from thesecond set of cylinders (e.g., cylinders 22 and 24). Likewise, an amountof exhaust gas from the second set of cylinders (e.g., cylinders 22 and23) may mix with an amount of exhaust gas from the first set ofcylinders (e.g., cylinders 20 and 26). Consequently, valve 154 in thesecond position may allow considerable mixing of exhaust gas directedvia the first scroll 100 and the second scroll 102 to turbine 92 in dualscroll turbocharger system 98.

As discussed above, valve 154 is in the second position may allowexhaust gas flow in the dual scroll system 98 “blow down” into a volumeof the valve assembly 145 formed between the first and second adaptors.As discussed, said volume has a larger volume as compared to a volume ineach individual scroll when valve 154 is closed (e.g., valve 154 in thefirst position). In this way, valve 154 in the second position may allowincreased exhaust flow communication and conveyance, such that thelarger volume in the valve assembly 145 may result in reduced pumpingwork and exhaust backpressure. Consequently, the second position mayincrease exhaust gas flow and energy to the turbine to increase boostpressure more rapidly, thereby increasing engine efficiency.

In one example, the valve 154 may be in the second position, or aposition substantially similar to the second position, during acondition when engine load is greater than the threshold load and/orengine speed is greater than a threshold speed. In another example,valve 154 may be adjusted to the second position based on other engineoperating conditions, such as turbine speed, desired boost pressure,and/or torque demand. As such, valve 154 in the second position mayprovide an amount of boost pressure to achieve the desired boostpressure while reducing exhaust manifold backpressure during high enginespeeds and/or loads.

Additional and/or alternative positions, or states, or ranges arepossible in accordance with the present disclosure. For example, valve154 may be opened a metered amount (herein referred to as a thirdposition), allowing partial mixing and merging of exhaust of the firstset of cylinders (e.g., cylinders 20 and 26) to the second set ofcylinders (e.g., cylinders 22 and 24) between the first scroll 100 andsecond scroll 102. Opening valve 154 the metered amount may compriseadjusting valve 154 such that angle 242 between each of the firstdivider 210 and second divider 212 relative to third divider 220 ofvalve 154 is between 15 and 75 degrees. In another example, openingvalve 154 the metered amount may comprise adjusting valve 154 such thatone or more angles formed between each of the first and second divider,and the third divider are acute angles. In this way, as compared to thevalve in the second position, valve 154 in the third position may reduceexhaust gas mixing of exhaust from one or more branches of the exhaustmanifold, and thus reduce mixing of the exhaust from the first set ofcylinders (e.g., cylinders 20 and 26) to the second set of cylinders(e.g., cylinders 22 and 24) since the metered amount of opening of valve154 may be limited.

In one example, valve 154 may be in the third position, or a positionsubstantially similar to the third position, when one or more of engineload is less than the threshold load, and/or engine speed is less thanthe threshold engine speed. In another example, the metered amount ofopening of valve 154 may be based on engine speed, engine load,wastegate position, and/or demanded torque. As such, in an example, themetered amount of opening of valve 154 may increase as engine load ordemanded torque decreases. In another example, the metered amount ofopening of valve 154 may increase as engine speed increases. In thisway, valve 154 in the third position may enable a desired amount ofcombining of exhaust gas responsive to one or more engine operatingconditions.

Thus, in one embodiment, a system having a dual scroll turbocharger maybe provided, comprising a first scroll, a second scroll, fluidicallyseparated from the first scroll via a dividing wall, a first adaptorcoupled to an outlet of an exhaust manifold, the first adaptorcomprising a first hollow cylinder having first divider traversing aninterior volume of the first adaptor, a second adaptor coupled to aninlet of the first scroll and an inlet of the second scroll, the secondadaptor comprising a second hollow cylinder comprising a second dividertraversing an interior volume of the second adaptor, and a valve coupledto and positioned between the first adaptor and the second adaptor tocontrol an amount of mixing of exhaust received from the exhaustmanifold, the exhaust delivered to the first scroll and the secondscroll of the turbocharger, the valve comprising a third hollow cylindercomprising a third divider traversing an interior volume of the valve.

In one example, the valve may be positionable in a continuous mannerthrough selected positions, the selected positions including: a firstposition wherein the valve is closed to separate exhaust flow to each ofthe first scroll and second scroll; a second position wherein the valveis open to enable mixing of exhaust flow to each of the first and secondscrolls; and a third position wherein the valve is opened a meteredamount to enable partial mixing of exhaust flow to each of the first andsecond scrolls.

Further, the valve, the first adaptor, and the second adaptor may sharea central axis. The valve may rotate about the central axis toselectively vary an orientation of the third divider of the valverelative to an orientation of each of the first divider of the firstadaptor and the second divider of the second adaptor, the central axisparallel to a direction of exhaust flow through each of the first scrolland the second scroll.

In another example, the first position may include the third divider ofthe valve being substantially aligned with the orientation of each ofthe first divider of the first adaptor and the second divider of thesecond adaptor, second position may include the third divider of thevalve being oriented substantially perpendicular to the orientation ofeach of the of the first divider of the first adaptor and the seconddivider of the second adaptor, and the third position may include thethird divider of the valve being oriented between 15 to 75 degreesrelative to the orientation of each of the first divider of the firstadaptor and the second divider of the second adaptor. In an example, thevalve may be adjusted to the first position to decrease mixing ofexhaust received from the exhaust manifold when engine speed is lessthan a speed threshold and engine load is less than a load threshold.Further, the valve may be adjusted to the second position to increase toincrease mixing of exhaust received from the exhaust manifold whenengine speed is greater than the speed threshold, and engine load isgreater than the load threshold. In another example, the valve may beadjusted to the third position from the first position when engine speedand/or engine load are increasing.

Referring now to FIGS. 4-6, a method, or routine, for adjusting aposition of a branch communication valve in response to engine operatingconditions, and a method, or routine, for adjusting a wastegate valvebased on the position of the branch communication valve are shown. Themethods or routines of FIGS. 4-6 may be at least partially incorporatedinto the system of

FIG. 1 as executable instructions stored in non-transitory memory.Further, the methods or routines of FIGS. 4-6 includes actions performedin the physical world. The methods or routines of FIGS. 4-6 may providethe operating sequence shown in FIG. 7. In other words, control methodsand routines disclosed herein, as shown in FIGS. 4-6, may be stored asexecutable instructions in non-transitory memory and may be carried outby the control system including the controller in combination with thevarious sensors, actuators, and other engine hardware.

FIG. 4 illustrates an example routine 400 for adjusting one or moremovable obstructions that are adjustable or positionable, such as valve154 shown in FIGS. 1-3, to provide multiple positions allowing mixing ofexhaust gas from one or more branches of an exhaust manifold, such asfirst set of cylinders (e.g., cylinders 20 and 26) and a second set ofcylinders (e.g., cylinders 22 and 24), to the first turbine inlet scroll(e.g., first scroll 100) and/or the second turbine inlet scroll (e.g.,second scroll 102) to a turbine (e.g., turbine 92). Specifically, aposition of the valve may be adjusted based on one or more engineoperating conditions and/or desired or demanded engine operations. Forexample, a position of the valve 154 may be responsive to an enginespeed and load, and a demanded torque requested by an operator of avehicle. In alternative examples, the position of valve 154 may beresponsive to other engine operating conditions, such as turbine speed,desired and/or measured boost pressure, and/or wastegate position. At402, routine 400 estimates and/or measures vehicle operating conditions.Vehicle operating conditions may be determined via receiving output ofsensors and actuators in the vehicle system. In one example, vehicleoperating conditions include but are not limited to engine temperature,driver demand torque, engine speed, vehicle speed, engine air-fuelratio, wastegate position, and distance traveled by the vehicle. Routine400 proceeds to 404 after determining vehicle operating conditions.

At 404, it may be determined if an engine speed is greater than apre-determined threshold speed and/or an engine load is greater than apre-determined threshold load. In one example, the threshold load may bean engine load at or above which high engine load may be present, suchas during hill-climbing or towing. In other words, the threshold engineload may be a condition above which high engine load (torque) isdemanded, engine load determined by various engine operating conditions.In another example, the threshold engine speed may be a speed or rangeof speeds at which increased backpressure in the exhaust manifold mayoccur. In yet another example, at 404, it may additionally oralternatively be confirmed if demanded torque is increasing.

If it is confirmed that one of an engine speed is greater than thethreshold engine speed and/or the engine load is greater than thethreshold engine load at 404, routine 400 continues to 406, where thevalve, such as valve 154 is adjusted to the second position, asdescribed in reference to FIGS. 2B and 3B, wherein valve 154 is rotatedsuch that the valve divider, e.g., third divider 220 of valve 154, isarranged substantially perpendicular to each of the dividers of thefirst adaptor 150 and second adaptor 152. As an example, valve 154 maybe rotated 90 degrees counterclockwise from the first position. In thisway, if one of an engine load is greater than the threshold load, enginespeed is greater than the threshold speed, and/or demanded torque isincreasing, routine 400 may adjust the valve to increase an amount ofexhaust gas that may be mixed via valve 154 directed to the turbine at406 in order to reduce risk of backpressure and increased pumping work.

If it is confirmed that one of the engine speed is less than thethreshold engine speed and/or the engine load is less than the thresholdengine load at 404, routine 400 proceeds to 408. At 408, it may bedetermined if one or more of an engine speed, engine load, and/or torquedemand are increasing. If it is not confirmed that one or more of theengine speed, engine load, and/or torque demand are increasing, thenroutine 400 proceeds to 410.

At 410, routine 400 may adjust valve 154 to the first position, asdescribed above with reference to FIGS. 2A and 3A. As such, the thirddivider 220 of valve 154 is substantially aligned with and parallel toeach of the first divider 210 of first adaptor 150 and second divider212 of second adaptor 152. In another example, the valve may be adjustedto a position substantially similar to the first position, such thatsubstantially all exhaust gas flow within each of the first scroll andthe second scroll are separately directed to the turbine. In this way,considerably all exhaust gas flow within each of the first and secondscroll may drive the turbine in order to provide a desired boostpressure when one of an engine speed is less than the threshold enginespeed (e.g., during low engine speed conditions) and an engine load isless than the threshold engine load (e.g., during low engine loadconditions).

However, if it is confirmed at 410 that one of an engine speed, engineload, and torque demand are increasing, routine 400 adjusts the valve154 to the third position at 412, as described above with reference toFIGS. 2 to 3. In one example, valve 154 may be adjusted to a positionsubstantially similar to the third position, such that the valve may beat least partially opened to each of the first and second scrolls toallow a portion of exhaust gas from the first and second set ofcylinders to combine and mix. As such, at 412, valve 154 may bepositioned between 15 to 75 degrees relative to the orientation of eachof the first divider of the first adaptor and the second divider of thesecond adaptor. In another example, valve 154 may be positioned suchthat one or more angles formed between each of the first and seconddividers, and the third divider are acute angles. Thus, a metered amountof exhaust gas from the first set of cylinders may mix and combine witha metered amount of exhaust gas from the second set of cylinders invalve assembly 145 of dual scroll system 98. In one embodiment, themetered amount of opening of valve 154 may be adjusted based on variousengine operating conditions. As an example, the angle 242 between eachof the first and second dividers may be adjusted from 15 degrees to 75degrees relative to the third divider. In one example, the meteredamount of opening may increase with increasing engine torque demandsand/or engine loads. In another example, the metered amount of openingof valve 154 may increase as engine speed increases. In this way,adjusting valve 154 to the third position may maintain or reduce boostpressure during a low engine speed, a low engine load, and/or low ordecreasing demanded torque, for example.

As a result, the valve in the third position, or a positionsubstantially similar to the third position, may allow mixing of ametered amount of exhaust gas from each of the first and second sets ofcylinders in the first and second scrolls to drive the turbine, e.g.,turbine 92. Thus, the third position of valve 154 may provide anincrease in boost pressure to meet an increasing demand for torque. Inanother example, the third position of valve 154 may provide an increasein boost pressure when one of an engine speed and/or engine load isincreasing but still less than their respective thresholds. After one ormore adjustments to valve 154 in response to one or more of an enginespeed, engine load, and/or demanded torque, routine 400 ends.

Thus, adjusting a branch communication valve, e.g., valve 154 may enableor disable mixing of exhaust received from the exhaust manifold, theexhaust delivered to the first scroll and the second scroll of aturbocharger. In other words, an amount of fluidic communication andconveyance of exhaust gas from each of the first and second set ofcylinders may also be adjusted by controller 12 based on various engineoperating conditions, such as engine load, engine speed, desired boost,and/or demanded torque. Consequently, an efficiency of the turbine (andturbocharger) and an amount of backpressure in the exhaust manifold maybe controlled to achieve desired boost level(s) and engine torque. Inother embodiments, adjusting the valve may provide the efficiency of theturbocharger and backpressure to be within predetermined range(s). Theefficiency may be determined, for example, by monitoring the intake airpressure, which may be measured, for example, with pressure sensor 132.Other engine sensors and/or sensors not currently described herein,and/or sensors that may not be used in current engine designs mayadditionally or alternatively be used. For example, an exhaust gas pulseprofile may be measured directly and/or determined by one or more sensorreadings, or other measures and inferred or calculated by a controller,e.g., controller 12.

Thus, a method for an engine is provided, comprising adjusting aposition of a valve arranged between a first adaptor and a secondadaptor to enable mixing of exhaust received from an exhaust manifoldresponsive to engine load and engine speed, the exhaust delivered to afirst scroll and a second scroll of a turbocharger, wherein the firstadaptor includes a first divider, the second adaptor includes a seconddivider, and the valve includes a third divider.

In particular, each of the first adaptor and second adaptor maystationary. The first divider of the first adaptor may bisect an innervolume of the first adaptor, the second divider of the second adaptormay bisect an inner volume of the second adaptor, and the third dividerof the valve may bisect an inner volume of the valve. In addition, eachof the valve, the first adaptor, and the second adaptor may share acentral axis, wherein the valve may rotate about the central axis toselectively vary a degree of alignment of the third divider of the valverelative to the first divider of the first adaptor and the seconddivider of the second adaptor, the central axis parallel to a directionof exhaust flow through each of the first scroll and the second scroll.

In one embodiment, adjusting the position of the valve may enable mixingof exhaust received from the exhaust manifold includes decreasing thedegree of alignment of the third divider of the valve relative to thefirst divider of the first adaptor and the second divider of the secondadaptor, and wherein adjusting the valve to enable mixing of exhaustreceived from an exhaust manifold includes increasing the degree ofalignment of the third divider of the valve relative to the firstdivider of the first adaptor and the second divider of the secondadaptor.

In another embodiment, the method may further comprise adjusting theposition of the valve to enable mixing of exhaust received from theexhaust manifold when engine speed is greater than a speed threshold andwhen engine load is greater than a load threshold, and adjusting theposition of the valve to disable mixing of exhaust received from anexhaust manifold when engine speed is less than the speed threshold andwhen engine load is less than a load threshold.

In one example, adjusting the position of the valve to enable mixing ofexhaust received from the exhaust manifold may include adjusting thevalve to a first position, the first position including the thirddivider of the valve being substantially aligned with each of the firstdivider of the first adaptor and the second divider of the secondadaptor. In another example, adjusting the position of the valve toenable mixing of exhaust received from the exhaust manifold may includeadjusting the valve to a second position, the second position includingthe third divider of the valve being substantially perpendicular to eachof the first divider of the first adaptor and the second divider of thesecond adaptor.

In yet another example, the method may include adjusting the position ofthe valve to enable partial mixing of exhaust received from the exhaustmanifold, wherein the adjusting the valve to enable partial mixing ofexhaust received from the exhaust manifold includes adjusting theposition of the valve to a third position, the third position includingthe third divider of the valve being positioned at an angle between 15to 75 degrees relative to each of the first divider of the first adaptorand the second divider of the second adaptor.

Further, the method may include increasing the angle between the thirddivider and each of the first divider of the first adaptor and thesecond divider of the second adaptor as engine speed and engine loadincreases, and decreasing the angle between the third divider and eachof the first divider of the first adaptor and the second divider of thesecond adaptor as engine speed and engine load decreases.

In another embodiment, the method may also comprise: in response to arequest for detecting cylinder imbalance, adjusting the valve to thefirst position from the second position or third position, measuring anair-fuel ratio in each of the first scroll and second scroll, andadjusting one of a fuel injection amount and throttle valve based on theair-fuel ratio in each of the first scroll and second scroll. In yetanother embodiment, the method may also comprise adjusting a degree ofopening of a wastegate based on the position of valve and engineoperating conditions.

Now turning to FIG. 5, an example routine 500 is shown for adjusting anamount of opening of one or more wastegates, such as first wastegate 104and/or second wastegate 108 of FIG. 1, in response to a position of oneor more movable obstructions, such as valve 154 shown in FIGS. 1-3.Adjustments to one or more wastegates based on the position of valve 154may be desirable since engine efficiency may vary depending on theposition of the valve 154 and one or more engine operating conditions.For example, a position of a wastegate valve of one or more wastegates(e.g., first wastegate 104 and/or second wastegate 108 of FIG. 1) may beresponsive to valve 154 being in the first position and/or secondposition, as discussed in reference to FIGS. 2-4, as well as to anengine speed and load, and/or a demanded torque requested by an operatorof a vehicle. In alternative examples, the position of the wastegatevalve may be responsive to other engine operating conditions, such asturbine speed, and desired versus measured boost pressure.

At 502, routine 500 estimates and/or measures vehicle operatingconditions. Vehicle operating conditions may be determined via receivingoutput of sensors and actuators in the vehicle system. In one example,vehicle operating conditions include but are not limited to enginetemperature, driver demand torque, engine speed, vehicle speed, engineair-fuel ratio, wastegate position, and distance traveled by thevehicle. Routine 500 proceeds to 504 after determining vehicle operatingconditions.

At 504, it may be determined if an engine speed is above apre-determined threshold speed and/or an engine load is above apre-determined threshold load. In one example, the threshold load may bean engine load at or above which high engine load may be present, suchas during hill-climbing or towing. In other words, the threshold engineload may be a condition above which high engine load (torque) isdemanded, wherein the high engine load may be based on various engineoperating conditions. In another example, the threshold engine speed maybe a speed or range of speeds at which increased backpressure in theexhaust manifold may occur.

If it is confirmed that the engine speed is greater than the thresholdengine speed and/or the engine load is greater than the threshold engineload at 504, the routine continues to 506, where the valve, such asvalve 154 is adjusted to the second position, as described in referenceto

FIGS. 2B and 3B. In the second position, the valve 154 is rotated suchthat the valve divider, e.g., third divider 220 of valve 154, isarranged substantially perpendicular to each of the dividers of thefirst adaptor 150 and second adaptor 152.

Further, in an alternative embodiment, the wastegate may be commanded tobe completely opened in response to the valve being in the secondposition. In this way, if one of an engine load is greater than thethreshold load and engine speed is greater than the threshold speed,routine 500 may completely open the wastegate to increase an amount ofexhaust gas that may be diverted from the turbine at 506, whileincreasing mixing of exhaust gas via valve 154 in order to reduce riskof backpressure and increased pumping work. Routine 500 then proceeds to508.

At 508, routine 500 determines if a measured boost pressure is greaterthan a desired boost pressure. In one example, the desired boostpressure may be a boost pressure responsive to varying engine speedand/or engine load. For example, the desired boost pressure may increasewith increasing engine speed and/or engine load. In another example, thedesired boost pressure may decrease with decreasing engine speed and/orengine load.

If the boost pressure is confirmed to be greater than the desired boostpressure, then a wastegate opening amount is increased at 510. As aresult, a greater amount of exhaust may bypass the turbine through thewastegate (e.g., first wastegate 104 and/or second wastegate 108)generated by the vehicle to reduce the boost pressure to the desiredboost pressure. Thus, a controller, e.g., controller 12, may adjust thewastegate responsive to a position of valve 154 and desired versusmeasured boost pressure. In this way, there may be a reduced risk ofexcessive thermal wear to the dual scroll turbocharger system 98.Routine 500 may then end. However, if it is confirmed at 508 that boostpressure is not greater than the desired threshold, then routine 500determines if the boost pressure is less than the desired boost pressureat 514. If the boost pressure is less than the desired boost pressure at514, then a wastegate opening amount is decreased at 518. As a result, areduced amount of exhaust may bypass the turbine through the wastegate(e.g., first wastegate 104 and/or second wastegate 108) to increase theboost pressure generated by the vehicle to the desired boost pressure.In this way, a controller, e.g., controller 12, may adjust the wastegateresponsive to a position of valve 154 and desired versus measured boostpressure. Routine 500 may then end.

If at 514, routine 500 does not confirm that boost pressure is less thanthe desired boost pressure, then routine 500 does not adjust wastegateat 516. Routine 500 may then end. If it is confirmed that the enginespeed is less than the threshold engine speed and/or the engine load isless than the threshold engine load at 504, the routine continues to520, where the valve, such as valve 154 is adjusted to the firstposition, as described in reference to FIGS. 2A and 3A. In the firstposition, valve 154 is rotated such that the valve divider, e.g., thirddivider 220 of valve 154, is arranged substantially aligned to each ofthe dividers of the first adaptor 150 and second adaptor 152. In anotherexample, the valve may be adjusted to a position substantially similarto the first position, such that substantially all exhaust gas flowwithin each of the first scroll and the second scroll are separatelydirected to the turbine since excessive backpressure may not be aconcern.

Further, in an alternative example, the wastegate may be commanded to bepartially closed in response to the valve being in the first position.In this way, considerably all exhaust gas flow within each of the firstand second scroll may drive the turbine in order to provide a desiredboost pressure when one of an engine speed is less than the thresholdengine speed (e.g., during low engine speed conditions) and an engineload is less than the threshold engine load (e.g., during low engineload conditions). Thus, if one of an engine load is less than thethreshold load and engine speed is less than the threshold speed,routine 500 may adjust the valve to reduce an amount of exhaust gas thatmay be mixed via valve 154 directed to the turbine at 514. Routine 500then proceeds to 516.

At 522, routine 500 determines if a measured boost pressure is greaterthan a desired boost pressure. In one example, the desired threshold maybe a boost pressure responsive to varying engine speed and/or engineload. For example, the desired boost pressure may increase withincreasing engine speed and/or engine load. In another example, thedesired boost pressure may decrease with decreasing engine speed and/orengine load.

If the measured boost pressure is confirmed to be greater than thedesired boost pressure, then a wastegate opening amount is increased at524. As a result, a greater amount of exhaust may bypass the turbinethrough the wastegate (e.g., first wastegate 104 and/or second wastegate108) generated by the vehicle to reduce the boost pressure to thedesired boost pressure. Thus, a controller, e.g., controller 12, mayadjust the wastegate responsive to a position of valve 154 and desiredversus measured boost pressure. In this way, there may be a reduced riskof excessive thermal wear to the dual scroll turbocharger system 98.Routine 500 may then end.

However, if it is confirmed at 522 that boost pressure is not greaterthan the desired, then routine 500 determines if the boost pressure isless than the desired boost pressure at 526. If the boost pressure isless than the desired boost pressure at 526, then a wastegate openingamount is decreased at 528. As a result, a reduced amount of exhaust maybypass the turbine through the wastegate (e.g., first wastegate 104and/or second wastegate 108) to increase the boost pressure generated bythe vehicle to the desired boost pressure threshold. In this way, acontroller, e.g., controller 12, may adjust the wastegate responsive toa position of valve 154 and desired versus measured boost pressure inorder to meet the desired boost pressure demands. Routine 500 may thenend.

If at 526, routine 500 does not confirm that boost pressure is less thanthe desired threshold, then routine 500 does not adjust wastegate at530. Routine 500 may then end.

Thus, one or more wastegates may be adjusted based on a position of abranch communication valve, e.g., valve 154, and various engineoperating conditions, such as engine load, engine speed, desired boost,and/or demanded torque. Consequently, an efficiency of the turbine (andturbocharger) may be controlled to achieve desired boost level(s) andengine torque. In this way, adjusting one or more wastegates may providethe efficiency of the turbocharger and backpressure to be withinpredetermined range(s).

Now turning to FIG. 6, an example routine 600 is shown for adjusting avalve, such as valve 154, to the first position from the second positionor third position, measuring an air-fuel ratio in each of the first andsecond scrolls, and adjusting one of a fuel injection amount andthrottle valve based on the air-fuel ratio in each of the first andsecond scrolls in response to a request for detection of a cylinderimbalance. Adjustments to valve 154 after a request for detection of acylinder imbalance may be desirable when the valve is the in the secondand/or third position. For example, when valve 154 is in the secondposition, exhaust gas from each of the first set of cylinders (e.g.,cylinders 20 and 26) and second set of cylinders (e.g., cylinders 22 and24) may mix and combine, thereby masking detection of variations incylinder exhaust output. Thus, adjustments to valve 154 may be desirablein order to sense cylinder imbalance.

At 602, routine 600 estimates and/or measures vehicle operatingconditions. Vehicle operating conditions may be determined via receivingoutput of sensors and actuators in the vehicle system. In one example,vehicle operating conditions include but are not limited to enginetemperature, driver demand torque, engine speed, vehicle speed, engineair-fuel ratio, wastegate position, and distance traveled by thevehicle. Routine 600 proceeds to 604 after determining vehicle operatingconditions.

At 604, a request for a cylinder imbalance monitoring may be initiated.In one example, the request for the cylinder imbalance detection modemay be based on the vehicle operating conditions, such as an air-fuelratio via one or more sensors, e.g., exhaust gas sensors 134 and 136.

Proceeding from 604, at 606, it is confirmed if the valve, e.g., valve154 arranged between the first and second adaptor as discussed inreference to FIGS. 1-3, is in the first position. For example, valve 154may be in the second and/or third position. As such, in order to detectand/or monitor cylinder imbalance, exhaust gas from each of the branchesof the exhaust manifold, e.g., first set of cylinders (e.g., cylinders20 and 26) and second set of cylinders (e.g., cylinders 22 and 24), maybe separated in order to reduce mixing of exhaust gas in the firstscroll 100 and second scroll 102.

Thus, at 608, if valve 154 is not confirmed to be in the first position(e.g., in the second or third position, as described in reference toFIGS. 1-3), valve 154 is adjusted to the first position. In other words,if valve 154 is in the second position, for example, such that thirddivider 220 of valve 154 is substantially perpendicular to each of thefirst and second divider, valve 154 is rotated in a continuous manner sothat the first, second, and third dividers are each aligned with oneanother. In one example, valve 154 may be rotated a first direction,such as direction 240 as discussed in reference to FIG. 3A, or a seconddirection, the second direction opposite the first direction. In thisway, valve 154 may be adjusted to reduce any fluidic communication andconveyance between the first scroll 100 and second scroll 102 in orderto monitor cylinder imbalance. Routine 600 then proceeds to 610.

If it is confirmed that valve 154 is in the first position at 606,routine 600 proceeds to 610. At 610, routine 600 determines if anair-fuel ratio in the first scroll 100 is substantially the same as anair-fuel ratio in the second scroll 102. Said determination may includedetecting and/or receiving a signal from the exhaust oxygen sensors. Inone embodiment, the determination of an air-fuel ratio in each of thefirst and second scrolls may include measurements by one or more exhaustgas sensors, e.g., exhaust gas sensors 134 and 136. As such, in oneexample, said determination at 610 may include routing exhaust gas froma group of cylinders to a desired exhaust gas sensor and/or routingexhaust gas from only a sub-set of the engine cylinders to the desiredexhaust sensor. Further, the signal detected for each of the exhaust gassensors may include a response of the exhaust gas sensor at or above aselected frequency. The detected signal may reflect air/fuel ratio ofindividual cylinders of the engine cylinder bank as the individualcylinders of that bank fire consecutively, and may be related tocylinder-to-cylinder air/fuel ratio dispersion of the cylinders in theengine cylinder bank.

If it is determined at 610 that the an air-fuel ratio in the firstscroll 100 is not substantially the same, or within an acceptable range,as an air-fuel ratio in the second scroll 102, then routine 600 mayadjust one or more fuel injection amount, ignition timing, and/orthrottle valve at 612 to compensate and/or correct for a detectedcylinder imbalance. In other examples, additional or alternativeadjustments to vehicle operating conditions may be provided.

However, if it is confirmed that the an air-fuel ratio in the firstscroll 100 is substantially the same, or within an acceptable range, asan air-fuel ratio in the second scroll 102, routine 600 proceeds to 614,wherein no adjustments to one or more fuel injection amount, ignitiontiming, and/or throttle valve may be performed. Routine 600 may thenterminate.

In this way, adjustments to valve 154 after a request for detection of acylinder imbalance may be desirable when the valve is the in the secondand/or third position in order reduce exhaust gas from each of the firstset of cylinders (e.g., cylinders 20 and 26) and second set of cylinders(e.g., cylinders 22 and 24) to mix and blend, masking recognition ofcylinder imbalance by the controller. As a result, reliable andeffective detection and monitoring of cylinder imbalance may beachieved.

FIG. 7 includes graph 700 illustrating example adjustments to a positionof a valve in response to engine operating conditions, including one ofan engine load, engine speed, and wastegate position. Specifically,graph 700 shows adjustments to valve position at plot 702, changes inengine load at plot 704, changes in engine speed at plot 706, changes inwastegate position at plot 708 and changes in boost pressure at plot710. The valve discussed in FIG. 7 may be a branch communication valve,as described above with reference to FIGS. 1-6. For example, the valveof FIG. 7 may be valve 154 depicted in FIGS. 2 and 3. Further, aposition of the valve in this example may be one of the first position(denoted by “1”), second position (denoted by “2”), and third position(denoted by “3”), as discussed above in reference to FIGS. 2 and 3. Inaddition, a wastegate in this example may be one of a first wastegate104 and second wastegate 108 described in reference to FIGS. 1 and 6.Time is plotted along the x-axis, and time increases from the left ofthe x-axis to the right. Further, a threshold engine load (e.g., T1) isrepresented by line 714 and a threshold engine speed (e.g., T2) is shownby line 716.

Prior to time t1, the engine is off such that no combustion isoccurring. At time t1, the engine is activated and may begin combusting.Between time t1 and time t2, the vehicle may be traveling along a roadwith a slight incline. Therefore, the engine load is graduallyincreasing, but remains below the threshold engine load T1 (e.g., line714). Similarly, engine speed is steadily increasing, but still remainsbelow the threshold engine speed T2 (e.g., line 716).

In response to the aforementioned engine operating conditions, the valvemay be adjusted to the third position (or a position substantiallysimilar to the third position) at time t1 and maintained in the thirdposition between time t1 and time t2. For example, in the thirdposition, the valve may be opened a metered amount such that an amountof exhaust gas from each of the branches of the exhaust manifold mayinteract to create turbulence upstream of the inlets of the first andsecond scrolls of the turbocharger. Further, engine pumping loss may bereduced by reducing pressure loss across the turbine. When the valve isopen, all exhaust gas from one or more cylinders may flow through bothscrolls, therefore reducing pressure loss due to an increase ofcross-section area of flow passage across the turbine. Thus, a meteredamount of exhaust gas from a first set of cylinders and a second,separate set of cylinders may mix and combine via valve 154 since bothengine speed and engine load are increasing. Further, between time t1and time t2, the wastegate may open, in a stepwise manner, from lessopen to more open to allow a portion of exhaust to bypass the turbineand exit through the wastegate.

At time t2, the vehicle may be traveling on a steeper incline road. Assuch, the engine load meets and then exceeds the threshold engine load,T1, above which the vehicle operator demands increased boost pressureand/or torque at time t2. Similarly, the engine speed reaches and thenexceeds the threshold engine speed, T2. As discussed above, thethreshold engine speed may be a speed at or above which excessive engineexhaust backpressure may occur in a dual scroll turbocharger system. Thevehicle continues to hill climb between time t2 and time t3, and bothengine speed and engine load are above their respective thresholds, T1and T2. Thus, the valve may be adjusted to the second position, or aposition substantially similar to the second position, wherein the valveis opened to each of the first and second scrolls. In this way, betweentime t2 and time t3, a portion of exhaust gas from each of the branchesof the exhaust manifold may interact to create turbulence upstream ofthe inlets of the first and second scrolls of the turbocharger. Further,engine pumping loss may be reduced by reducing pressure loss across theturbine. When the valve is open, all exhaust gas from one or morecylinders may flow through both scrolls, therefore reducing pressureloss due to an increase of cross-section area of flow passage across theturbine. In this way, there may be a reduction in backpressure andpumping work while increasing an amount of exhaust gas to the turbine toincrease measured boost pressure to meet the desired boost pressure.Therefore, the wastegate is adjusted to a more open position in order toroute a substantial portion of the exhaust to the wastegate. At time t3,the vehicle is not hill climbing, but instead, is traveling on a roadhaving less incline. In other examples, the vehicle may be movingdownhill. In the aforementioned examples, the engine load decreasesbelow the threshold engine load. However, engine speed is still abovethe threshold engine speed. Consequently, the boost pressure decreasesin response to declining engine load, and the valve is adjusted to thethird position, or a position substantially similar to the thirdposition, between time t3 and time t4. In the third position, the valveis opened a metered amount, such that the divider of the valve may beangled at 75 degrees relative to the dividers of the first and secondadaptor. As a result, an amount of exhaust gas mixes and combines toreduce risk of backpressure due to a higher engine speed, but to alesser degree than in the second position. Between time t3 and time t4,the wastegate is adjusted to the half open position since engine load isdecreasing. In other examples, the valve may move to the first positionbetween time t3 and time t4.

At time t4, the vehicle continues moving downhill or on a road withlittle incline, and the engine speed decreases below the thresholdengine speed, T2. Further, the engine load continues to steadilydecrease, thereby reducing desired boost pressure between time t4 andtime t5. In this example, the desired boost pressure and measured boostpressure is substantially the same between time t4 and time t5. Sinceengine load and boost pressure are not increasing, the valve is adjustedto the first position to decrease an amount of exhaust flow mixing,wherein the valve, e.g., valve 154, is closed to each of the first andsecond scrolls. Thus, boost pressure concomitantly decreases. Moreover,between time t4 and time t5, the wastegate is in the more closedposition to direct a portion of exhaust gas towards the turbine.

At time t5, the vehicle again begins to travel uphill, for example. Inanother example, the vehicle may be towing a trailer. As shown in thisexample, each of the engine speed and engine load is increasing, but hasnot yet reached the threshold engine speed and threshold engine load,respectively. Because the measured engine load has not met the thresholdengine load, and the measured engine speed has not met the thresholdengine speed, the valve is adjusted to the third position, or a positionsubstantially similar to the third position. As discussed, in the thirdposition, the valve is opened a metered amount, such that the divider ofthe valve may be angled at 75 degrees relative to the dividers of thefirst and second adaptor, in one example. As a result, an amount ofexhaust gas may mix and combine to reduce risk of backpressure due to anincreasing engine speed. Boost pressure concomitantly increases.Moreover, the wastegate may be adjusted to the half open position inorder to route a portion of the exhaust to the turbine between time t5and time t6. In this way, the third position allows an amount of exhaustflow to drive the turbine to meet an increasing torque demand.

At time t6, the engine load and engine speed both reach and/or exceedthe threshold engine load, T1, and threshold engine speed, T2, in thisexample. In response to each of the engine load exceeding the thresholdengine load and the engine speed exceeding than the threshold enginespeed, the valve may be adjusted to the second position, or a positionsubstantially similar to the second position, to allow mixing of exhaustgas from the first and second set of cylinders, and direct substantiallyall exhaust gas flow within the first and second scrolls to the turbine,thereby increasing torque and boost pressure. As such, boost pressureconcomitantly increases. Further, the wastegate is in the more openposition to increase escape of exhaust gas through the wastegate betweentimes t6 and t7. In this way, there may be a reduction in backpressureand pumping work while driving a desired amount of exhaust to theturbine responsive to high engine loads and engine speeds.

At time t7, the vehicle begins traveling on a road having little to noincline, such that engine load and engine speed each fall below thethreshold engine load, T1, and threshold engine speed, T2. In responseto each of the decreasing engine load and engine speed, the valve isadjusted to the first position. In the first position, the valve isclosed completely to each of the first and second scrolls. As such,boost pressure decreases. Moreover, between time t7 and time t8, thewastegate is adjusted to a half open and/or less open position. In thisway, an amount of exhaust gas in each of the first and second scrollsmay be directed to the turbine. At time t8, a vehicle cycle comprisingall events between time t1 and time t8 ends.

The technical effect of adjusting a position of a valve arranged betweena first adaptor and a second adaptor to enable mixing of exhaustreceived from an exhaust manifold is the reduction of backpressure andpumping work in response to varying engine load and engine speed. Inparticular, engine pumping loss may be reduced by reducing pressure lossacross the turbine. When the valve is open, all exhaust gas from one ormore cylinders may flow through both scrolls, therefore reducingpressure loss due to an increase of cross-section area of flow passageacross the turbine. Thus, there may be increased engine efficiency andfuel economy during desired engine operating conditions. Further, theremay be a reduction in cost, weight, and packaging penalties associatedwith including a simple valve assembly system in the turbocharger andengine system, as compared to installing a branch communication valvehaving multiple components, such as valve plates, hinges, and recesses.There may also be less burden on an engine control and monitoring systemwhen only a single valve is adjustable by the aforementioned systembased on engine operating conditions.

Thus, in one embodiment, an engine system may be provided comprising: afirst passage for fluid conveyance from a first branch of combustionchambers to a turbine; a second passage for fluid conveyance from asecond branch of combustion chambers to the turbine, and separated fromthe first passage by a dividing wall; a first adaptor coupled to anoutlet of the first branch of combustion chambers and an outlet of thesecond branch of combustion chambers, the first adaptor having a firstdivider spanning an inner volume of the first adaptor; a second adaptorcoupled to an inlet of the first passage and an inlet of the secondpassage, the second adaptor having a second divider spanning an innervolume of the second adaptor; and a valve positioned between the firstadaptor and the second adaptor for selectively allowing fluid from oneof the first and second branches of combustions chambers to another ofthe first and second branches of combustion chambers, the valve having athird divider spanning an inner volume of the valve.

In one embodiment, the valve may rotate about a central axis toselectively control a position of the valve relative to the firstadaptor and the second divider of the second adaptor, the central axisparallel to a direction of exhaust flow through each of the firstpassages and the second passages. The valve may positionable via asignal received from a controller in a continuous manner throughselected ranges including: wherein the valve is in a first position whenengine load is less than a threshold engine load and engine speed isless than a threshold engine speed; and wherein the valve is in a secondposition when engine load is greater than the threshold engine load andengine speed is greater than the threshold engine speed.

In one example, the first position may include the third divider of thevalve being aligned with the first divider of the first adaptor and thesecond divider of the second adaptor, and the second position mayinclude the third divider of the valve being arranged perpendicular tothe first divider of the first adaptor and the second divider of thesecond adaptor.

In another representation, a method for an engine is provided, adjustinga valve to provide one of a separation of exhaust and mixing of exhaust,wherein the valve varies a degree of mixing of exhaust received from anexhaust manifold. Specifically, the valve may vary the degree of mixingby rotating about the central axis to selectively vary a degree ofalignment of the third divider of the valve relative to the firstdivider of the first adaptor and the second divider of the secondadaptor, the central axis parallel to a direction of exhaust flowthrough each of the first scroll and the second scroll.

In one example, the valve may vary the degree of mixing by decreasingthe degree of alignment of the third divider of the valve relative tothe first divider of the first adaptor and the second divider of thesecond adaptor, or increasing the degree of alignment of the thirddivider of the valve relative to the first divider of the first adaptorand the second divider of the second adaptor.

Note that the example control and estimation routines included hereincan be used with various engine and/or vehicle system configurations.The control methods and routines disclosed herein may be stored asexecutable instructions in non-transitory memory and may be carried outby the control system including the controller in combination with thevarious sensors, actuators, and other engine hardware. The specificroutines described herein may represent one or more of any number ofprocessing strategies such as event-driven, interrupt-driven,multi-tasking, multi-threading, and the like. As such, various actions,operations, and/or functions illustrated may be performed in thesequence illustrated, in parallel, or in some cases omitted. Likewise,the order of processing is not necessarily required to achieve thefeatures and advantages of the example embodiments described herein, butis provided for ease of illustration and description. One or more of theillustrated actions, operations and/or functions may be repeatedlyperformed depending on the particular strategy being used. Further, thedescribed actions, operations and/or functions may graphically representcode to be programmed into non-transitory memory of the computerreadable storage medium in the engine control system, where thedescribed actions are carried out by executing the instructions in asystem including the various engine hardware components in combinationwith the electronic controller.

In combination with any of the above methods and systems, adjusting aposition of a valve arranged between a first adaptor and a secondadaptor to enable mixing of exhaust received from an exhaust manifoldresponsive to engine load and engine speed, the exhaust delivered to afirst scroll and a second scroll of a turbocharger, wherein the firstadaptor includes a first divider, the second adaptor includes a seconddivider, and the valve includes a third divider.

In combination with any of the above methods and systems, each of thefirst adaptor and second adaptor are stationary, and wherein the firstdivider of the first adaptor bisects an inner volume of the firstadaptor, the second divider of the second adaptor bisects an innervolume of the second adaptor, and the third divider of the valve bisectsan inner volume of the valve.

In combination with any of the above methods and systems, each of thevalve, the first adaptor, and the second adaptor share a central axis,and wherein the valve rotates about the central axis to selectively varya degree of alignment of the third divider of the valve relative to thefirst divider of the first adaptor and the second divider of the secondadaptor, the central axis parallel to a direction of exhaust flowthrough each of the first scroll and the second scroll.

In combination with any of the above methods and systems, adjusting theposition of the valve to enable mixing of exhaust received from theexhaust manifold when engine speed is greater than a speed threshold andwhen engine load is greater than a load threshold, and adjusting theposition of the valve to disable mixing of exhaust received from anexhaust manifold when engine speed is less than the speed threshold andwhen engine load is less than a load threshold.

In combination with any of the above methods and systems, adjusting theposition of the valve to enable mixing of exhaust received from theexhaust manifold includes adjusting the valve to a first position, thefirst position including the third divider of the valve beingsubstantially aligned with each of the first divider of the firstadaptor and the second divider of the second adaptor.

In combination with any of the above methods and systems, adjusting theposition of the valve to enable partial mixing of exhaust received fromthe exhaust manifold, wherein the adjusting the valve to enable partialmixing of exhaust received from the exhaust manifold includes adjustingthe position of the valve to a third position, the third positionincluding the third divider of the valve being positioned at an anglebetween 15 to 75 degrees relative to each of the first divider of thefirst adaptor and the second divider of the second adaptor. Incombination with any of the above methods and systems, increasing theangle between the third divider and each of the first divider of thefirst adaptor and the second divider of the second adaptor as enginespeed and engine load increases, and decreasing the angle between thethird divider and each of the first divider of the first adaptor and thesecond divider of the second adaptor as engine speed and engine loaddecreases.

In combination with any of the above methods and systems, comprising inresponse to a request for detecting cylinder imbalance, adjusting thevalve to the first position from the second position or third position,measuring an air-fuel ratio in each of the first scroll and secondscroll, and adjusting one of a fuel injection amount and throttle valvebased on the air-fuel ratio in each of the first scroll and secondscroll.

In combination with any of the above methods and systems, furthercomprising adjusting a degree of opening of a wastegate based on theposition of valve and engine operating conditions.

In combination with any of the above methods and systems, adjusting theposition of the valve to enable mixing of exhaust received from theexhaust manifold may include decreasing the degree of alignment of thethird divider of the valve relative to the first divider of the firstadaptor and the second divider of the second adaptor, and whereinadjusting the valve to enable mixing of exhaust received from an exhaustmanifold includes increasing the degree of alignment of the thirddivider of the valve relative to the first divider of the first adaptorand the second divider of the second adaptor.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to V-6,I-4, I-6, V-12, opposed 4, and other engine types. The subject matter ofthe present disclosure includes all novel and non-obvious combinationsand sub-combinations of the various systems and configurations, andother features, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

1-11. (canceled)
 12. A system having a dual scroll turbocharger,comprising: a first scroll; a second scroll, fluidically separated fromthe first scroll via a dividing wall; a first adaptor coupled to anoutlet of an exhaust manifold, the first adaptor comprising a firsthollow cylinder having first divider traversing an interior volume ofthe first adaptor; a second adaptor coupled to an inlet of the firstscroll and an inlet of the second scroll, the second adaptor comprisinga second hollow cylinder comprising a second divider traversing aninterior volume of the second adaptor; and a valve coupled to andpositioned between the first adaptor and the second adaptor to controlan amount of mixing of exhaust received from the exhaust manifold, theexhaust delivered to the first scroll and the second scroll of theturbocharger, the valve comprising a third hollow cylinder comprising athird divider traversing an interior volume of the valve.
 13. The dualscroll turbocharger system of claim 11, wherein the valve ispositionable in a continuous manner through selected positions, theselected positions including: a first position wherein the valve isclosed to separate exhaust flow to each of the first scroll and secondscroll; a second position wherein the valve is open to enable mixing ofexhaust flow to each of the first and second scrolls; and a thirdposition wherein the valve is opened a metered amount to enable partialmixing of exhaust flow to each of the first and second scrolls.
 14. Thesystem of claim 13, wherein each of the valve, the first adaptor, andthe second adaptor share a central axis, and wherein the valve rotatesabout the central axis to selectively vary an orientation of the thirddivider of the valve relative to an orientation of each of the firstdivider of the first adaptor and the second divider of the secondadaptor, the central axis parallel to a direction of exhaust flowthrough each of the first scroll and the second scroll.
 15. The systemof claim 14, wherein the first position includes the third divider ofthe valve being substantially aligned with the orientation of each ofthe first divider of the first adaptor and the second divider of thesecond adaptor, wherein the second position further includes the thirddivider of the valve being oriented substantially perpendicular to theorientation of each of the of the first divider of the first adaptor andthe second divider of the second adaptor, and wherein the third positionfurther includes the third divider of the valve being oriented between15 to 75 degrees relative to the orientation of each of the firstdivider of the first adaptor and the second divider of the secondadaptor.
 16. The system of claim 15, wherein the valve is adjusted tothe first position to decrease mixing of exhaust received from theexhaust manifold when engine speed is less than a speed threshold andengine load is less than a load threshold, wherein the valve is adjustedto the second position to increase to increase mixing of exhaustreceived from the exhaust manifold when engine speed is greater than thespeed threshold, and engine load is greater than the load threshold, andwherein the valve is adjusted to the third position from the firstposition when engine speed and/or engine load are increasing.
 17. Anengine system comprising: a first passage for fluid conveyance from afirst branch of combustion chambers to a turbine; a second passage forfluid conveyance from a second branch of combustion chambers to theturbine, and separated from the first passage by a dividing wall; afirst adaptor coupled to an outlet of each of the first branch ofcombustion chambers and second branch of combustion chambers, the firstadaptor having a first divider spanning an inner volume of the firstadaptor; a second adaptor coupled to an inlet of the first passage andan inlet of the second passage, the second adaptor having a seconddivider spanning an inner volume of the second adaptor; and a valvepositioned between the first adaptor and the second adaptor forselectively allowing fluid from one of the first and second branches ofcombustions chambers to another of the first and second branches ofcombustion chambers, the valve having a third divider spanning an innervolume of the valve.
 18. The engine system of claim 17, wherein thevalve rotates about a central axis to selectively control a position ofthe valve relative to the first adaptor and the second adaptor, thecentral axis parallel to a direction of exhaust flow through each of thefirst passage and the second passage.
 19. The engine system of claim 17,wherein the valve is positionable via a signal received from acontroller in a continuous manner through selected ranges including: afirst position when engine load is less than a threshold engine load andengine speed is less than a threshold engine speed; and a secondposition when engine load is greater than the threshold engine load andengine speed is greater than the threshold engine speed.
 20. The enginesystem of claim 19, wherein the first position includes the thirddivider of the valve being aligned with the first divider of the firstadaptor and the second divider of the second adaptor, and wherein thesecond position includes the third divider of the valve being arrangedperpendicular to the first divider of the first adaptor and the seconddivider of the second adaptor.